An enormous debris cloud is accumulating in the Earth's atmosphere. The debris cloud primarily comprises spent rocket bodies, dead satellites, and fragments generated when such objects collide. For example, in January 2007, China conducted its first anti-satellite missile test, destroying a Chinese weather satellite. As another example, in February 2009, a dead Russian military satellite slammed into an active U.S. communications satellite, creating two new clouds of space junk. NASA estimates that there are about 22,000 pieces as large as a softball, 500,000 pieces of space debris bigger than a marble, and hundreds of millions of flecks at least 1 millimeter in diameter. These pieces are moving so fast that any one of them could knock out one of the 1,000 or so operational satellites. That is a non-trivial potential problem, given increasing societal dependence on satellite communications, particularly in remote regions of the Earth.